1. Field of the Invention
The invention concerns an optical body which serves for coupling in, passing on and emitting the light delivered by a light source in a conical spatial region, wherein the optical body has a light emission surface and a recess which is opposite thereto and which has a longitudinal axis and in which the light source can be so positioned that the central axis of the conical spatial region coincides with the longitudinal axis of the recess and wherein the recess has an annularly closed inner peripheral wall which surrounds the longitudinal axis and a cover wall which extends transversely relative to its longitudinal axis and in which there is provided an optical structure for altering the spread angle of the light beam passing therethrough, and to a vehicle light which is equipped with at least one such optical body.
2. Description of Related Art
Optical bodies of the above-indicated type are known, for example, from German Patent Application DE 10 2004 026 530 B3 and corresponding U.S. Patent Application Publication 2005/0265041 A1. These bodies are flat plate-shaped bodies which comprise a light-conducting material and which have two main surfaces extending approximately parallel to a main central plane defined by XZ-coordinates, from which they are at equally spaced in the Y-direction perpendicular to the XZ-coordinates, and the vertical projections of which (in the Y-direction) on to the XZ-plane are coincident.
Each of these known optical bodies has a respective base portion having a cylindrical recess in which a lighting means, for example, an LED, can be introduced to such an extent that the light delivered thereby into a conical solid angle region passes practically completely into the optical body, wherein the light cone delivered by the LED and the recess have a common central axis extending parallel to the Z-direction. Light entry is affected, in part, by way of the inner cylindrical peripheral wall, and in part, by way of the cover surface of the recess, that is in opposite relationship to the LED, wherein a convergent optical means is provided in that cover surface. The optical body is of a mirror-symmetrical configuration with respect to the plane extending through the central axis and perpendicular to the XZ-plane and is of an approximately V-shape configuration so that it has two arms which extend in the light propagation direction and away from the central axis and whose side surfaces, that connect the main surfaces together, serve to distribute in particular the light which has entered through the side wall of the recess in the X-direction by total reflection and to pass it on in the Z-direction. On their light emission surface connecting the main surfaces, the legs of the V-shape of the optical body have additional optical elements in order to distribute the light issuing here into the medium air, over a region which is as wide as possible. A plurality of such optical bodies can be so connected together that their main central planes are aligned with each other and two adjacent optical bodies touch each other in the region of the tips of their V-legs. For such an arrangement that includes a plurality of optical bodies, there is provided a frontally disposed optical means which is common to all of the optical bodies and which is separated from the light emission surfaces of the optical bodies by an air gap and by means of which the actual desired lighting function of the respective vehicle light in which the optical body arrangement is to be fitted is achieved.
The known optical bodies suffer from the following series of disadvantages:
There are comparatively long light paths in the light-conducting medium and the light has to pass through a total of four interfaces (two of each optical body and two of the frontally disposed optical means). That therefore gives rise to light losses.
Difficulties in terms of production engineering occur in particular when the attempt is made to form the frontally disposed optical means in one piece with the optical body or bodies. If the frontally disposed optical means is produced in the form of an independent component, the assembly expenditure is increased.
Both the individual optical bodies and also the frontally disposed optical means have to be adapted to the respectively desired lighting function, in respect of the geometrical configuration.
As the apex point of the light cone emitted by an LED is at a different spacing in the direction of the central axis, depending on the respective LED type, from the mounting base of the LED, generally a printed circuit board, that is to be fixedly connected to the rear side of the optical bodies, the optically active surfaces of the optical elements which are intended to render parallel the light passing into the optical body and to pass it on to the light emission side, have to be adapted to the respective type of LED.
In particular, the requirement that the optical bodies have to be adapted both to the lighting function to be achieved and also to the LEDs used leads to a considerable increase in the cost of their manufacture.